Dispersal projectile



March 25, 1969 Q ET AL 3,434,420

DISPERSAL PROJECTILE Filed Jan. 30. 1968 M M EK 0N0. W: TOU #5 NC Y E E v..w w N00 0 I K Q T F 0A 8 M ma mm M m 1 United States Patent Office US. Cl. 102-56 4 Claims ABSTRACT OF THE DISCLOSURE A small arms projectile having a hypersensitive, throughbulkhead type, explosive fuze in its nose portion and a chamber for propellant actuated liquid or solid dispersal in its body portion for dispersal through the rear of the projectile.

The invention described herein may be manufactured, used and licensed by or for the Government for governmental purposes without the payment to us of any royalty thereon.

The invention relates to a projectile and more particularly to a small arms projectile having a throughbulkhead type fuze means which causes the dispersal of a liquid or solid agent out through the rear of the projectile.

In the past, dispersal projectiles requiring impact initiation at the target have been vented through the projectile nose. This type of projectile is obviously undesirable where the projectile continues in flight after striking the initial target. Prior art projectiles which were hypersensitive on impact were also sensitive in flight and undesirable because of premature ignition caused by inclement weather.

The present invention eliminates the aforesaid problem by providing a dispersal projectile which is only sensitive upon impact and which disperses its contents out through the rear.

It is therefore an object of the present invention to provide a projectile which retains the advantages of ballistically stable projectiles while being sensitive only to impact initiation.

Another object is the provision of a projectile having a hypersensitive through-bulkhead, type of nose fuze asembly.

A further object is to provide a dispersal projectile which is sensitive to impact and disperses its contents out through the rear.

The above objects as well as others together with the benefits and advantages of the invention will be apparent upon reference to the detailed description set forth below, particularly when taken in conjunction with the drawing annexed hereto in which a projectile is indicated generally by reference character 10.

The projectile is comprised of two main portions, namely nose portion 12 and body portion 14. Both portions are contained in a metallic jacket 16 which is open at both ends. The nose portion 12 consists of a metal or ceramic nose piece 18 which has a cavity 20 corresponding, at its forward end, with the jacket opening. The cavity 20 is covered along with a portion of the jacket 16 by a thin plastic shield 21 made of polyethylene, polypropylene or the like, which adheres to the jacket by virtue of an adhesive coating such as an epoxy resin applied to the interior of the plastic shield. Located at the rear of said cavity 20 is a detonator 22 containing ignition-sensitive, priming explosive materials, such as lead styphnate, diazodinitrophenol, mercury fulminate, tetracene and lead azide. The remaining portion of the cavity constitutes an air gap 23. A second cavity 24, co-axial with the first mentioned cavity, is located through-bulk- 3,434,420 Patented Mar. 25, 1969 head from said detonator and contains a primary explosive charge 26, such as lead styphnate, diazodinitrophenol, mercury fulminate, tetraoene and lead azide, compressed to 30,000 lbs. to achieve maximum density. Adjacent said primary explosive charge is a solid propellant charge 28 of double base or composite propellant contained in a cavity 30, also co-axial with the other previously mentioned cavities, which is of a larger diameter than those previously mentioned. Adjacent said propellant charge and said nose piece 18 is a thin seal 32 constructed of an epoxy adhesive-coated plastic, paper, or rubber which separates the nose portion 12 from the body portion 14. The body portion 14 of the projectile 10 includes a liquid or solid filler substance 34 which is separated from the nose portion 12 by said seal 32. A metallic base plug 36 is secured in the open rear of said jacket 16 to contain the filler substance 34 therein.

In operation, the projectile is fired from a standard small arms weapon. Upon muzzle exit, the projectile has passed through maximum acceleration cycle, and has attained a relatively constant velocity. Upon impact on a target, e.g., as thin as a window pane, the plastic shield 21 shears radially along the edge of the hole in the nose of the jacket 16. The shorn portion compresses the air in the air gap 23, heating up this air to such a temperature that heat transfers from the air to the detonator 22, is sufficient to ignite and thereby initiate the primary high explosive in the detonator 22. This temperature range is from 340 C. to 600 C., depending upon the impact energy and the particular explosive used. This initiation generates a shock wave pattern throughout the nose piece material. In particular, energy from those shock waves exiting the nose piece material in the vicinity of the primary high explosive charge 26 is suflicient to initiate said charge directly whereupon the adjacent propellant 28 is ignited by virtue of the energy transferred from charge 26. Gas pressure generated from the propellant 28 proceeds to force out the base plug 36, by transferring force hydraulically through the incompressible filler 34. The total effect of this gas is to disperse the filler 34 to the immediate atmosphere in the area of initial target impact. During the explosive initiation and propellant combustion, the nose portion 12 of the projectile 10 remains unvented because the nose piece is intact and integral during and after all initiation and combustion proc esses.

The optimum volume and length of the air gap cavity 20, for reliable ignition is determined by the projectile and detonator sizes, shapes and masses. Air cavity length should generally be or more the length of the total detonator column in the nose piece. This would permit the shorn portion of the plastic shield to sufiiciently compress the entrapped air to a temperature capable of igniting primary explosives.

We claim:

1. A dispersal projectile comprised of a nose portion including a unitary nose piece defining a plurality of coaxial cavities including a first cavity communicating with a forward end of said nose piece, a second cavity spaced apart from said first cavity, and a third cavity communicating with a rearward end of said nose piece and located adjacent said second cavity,

a plastic shield having a thick central portion covering said first cavity at its forward open end and extending beyond the forward end of said nose piece having a thin peripheral portion overlapping said nose piece adjacent its open end,

a detonator contained in the rear closed portion of said first cavity,

3 4 an air gap sealed within said first cavity between 4. A projectile of the type described in claim 1 wheresaid shield and said detonator, in said plastic shield is made of a material selected from a primary high explosive charge contained in said the group consisting of polyethylene and polypropylene.

second cavity, a propellant contained in said third cavity, 5 References C t a seal covering said third cavity adjacent its rear- UNITED STATES PATENTS 355d end and the bottom of sand nose plece, 1,878,491 9/1932 GOSS 102 90 a base portion including 2 56, 98 9/19 6 Gaylak 7 1 256 a finer contained therein and 2,401,380 6/1936 Teltscheld 10252 10 2 406 135 8/1946 Chavez 10290 a base plug releasably secured thereto whereupon impact of said projectile said shield shears to 263O066 3/1953 Ponder et 102 6 3,289,588 12/1966 Hitchens et a1. 1026O permit the central portion of said shield to be forced into said air gap to compress and heat OTHER REFERENCES the air therein which ignites said projectile there- 1 t by resulting in ultimate expulsion of said filler. Cook' The Sclence of Hlgh Exploslves 1958 p. 4'

2. A projectile of the type described in claim 1 in- BENJAMIN BORCHELT Primary Examiner. eluding a metallic jacket, open at either end, covering both said nose and said base portion. JAMES Asslslam Examiner- 3. A projectile of the type described in claim 1 where- 20 U S Cl X R in said third cavity is of a larger diameter than said sec- 0nd cavity. 102 90 

